• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.3
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• pp.58-63
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• 2009

The global restriction on pollutant emissions and the soaring of crude oil price are expected to result in the change of future transportation system. Hydrogen is considered to be the leading candidate as an alternative energy source before other new alternative energy sources emerge. Scientists anticipate that hydrogen fuel gas turbine engine and fuel cell will be the power plant of the aircraft in the near future. To realize the aircraft powered by fuel cell system in the future, the technologies such as fuel cell with higher energy density, compressed gas or liquid storage system of hydrogen fuel, and efficient and lightweight electric motor have to be developed first.

• Journal of Aerospace System Engineering
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• v.18 no.3
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• pp.8-16
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• 2024

Because hydrogen has very low density, a different storage method is required to store the same amount of energy as fossil fuel. One way to increase the density of hydrogen is through liquefaction. However, since the liquefied temperature of hydrogen is extremely low at -252 ℃, it is easily vaporized by external heat input. When liquid hydrogen is vaporized, a self-pressurizing phenomenon occurs in which the pressure inside the hydrogen tank increases, so when designing the tank, this rising pressure must be carefully predicted. Therefore, in this paper, the internal pressure of a cryogenic liquid fuel tank was predicted according to the liquid hydrogen filling ratio. A one-dimensional thermodynamic model was applied to predict the pressure rise inside the tank. The thermodynamic model considered heat transfer, vaporization of liquid hydrogen, and fuel discharging. Finally, it was confirmed that there was a significant difference in pressure behavior and maximum rise pressure depending on the filling ratio of liquid hydrogen in the fuel tank.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.184-190
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• 2014

Fuel cell power system, unlike conventional energy sources, converts chemical energy into electrical energy through electrochemical reaction of hydrogen and oxygen. In recent years, railway field as well as mobile fuel cell power system is being studying actively with development of hydrogen storage technologies. This paper presents the feasibility study on small-scale prototype electric railway vehicle application using fuel cell generation system. it is confirmed that proposed fuelcell-battery hybrid system shows good response characteristic about speed and torque based on design of parameter on system. Also as results of response for proposed system modeling, it show that powering mode and braking mode of system is controlled by switching devices of converters.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.3
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• pp.216-223
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• 2009

The relation between temperature and hydrogen desorption on variation in output was investigated for the metal hydride canister. For this study, an AB$_5$ type alloy were chosen as a hydrogen storage material in the metal hydride canister. And application to the single proton exchange membrane fuel cell was evaluated. As the results, the hydrogen desorption was linearly increased as the temperature was risen. In addition, metal hydride canister heating was able to correspond the variation of load as power request in the PEMFC system.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.331-337
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• 2017

Proton Exchange Membrane Water Electrolysis (PEMWE) is one of the most popular and widely used methods for hydrogen production. PEMWE contributes to eco-friendly system via its energy storage system application, hence making it environmentally friendly to use. However, its main drawback is contamination of proton exchange membrane during water electrolysis. Existing cation such as magnesium, calcium and the likes are the cause for membrane contamination. As a result, the cation contamination give rise to degradation of performance of electrolysis and the reverse electrolysis is effective method to remove cation.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.1
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• pp.40-47
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• 2024

Ammonia is drawing attention as carbon free fuel due to its ease of storage and transportation compared to hydrogen. This study suggests ammonia fueled solid oxide fuel cell (SOFC) system with electrochemical hydrogen compressor (EHC)-based recirculation. Performance of electrochemical hydrogen pump is based on the experimental data under varying hydrogen and nitrogen concentration. As a result, the suggested system shows 62.04% net electrical efficiency. The efficiency is 10.33% point higher compared to simple standalone SOFC system (51.71%), but 0.02% point lower compared to blower-based recirculation system (62.06%). Further improvement in the EHC-based SOFC recirculation system can be achieved with EHC performance improvement.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.519-522
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• 2004

In the course of anaerobic storage of excess sludge, odors due to chemicals such as hydrogen sulfide are produced. These odors cause many problems. Many methods have been developed to eliminate odors, but all current methods are not only costly, but also largely inef­fective. In this paper, we investigate the process of transformation of sludge microorganism cul­tures through intense aeration under nutrient-poor conditions, in terms of the selective adjust­ment and control of microorganism culture. The aerated sludge is subsequently returned to the adjusting pool, where the microorganisms inhibit odors, thus the excess sludge itself will act as an odor inhibitor. The process can be verified in terms of viability, in that the degradation capac­ity of the sludge was maintained after the intensely-aerated sludge was returned to the treat­ment system.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.203-206
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• 2005

The objective of study on composite cylinder for alternative fuel vehicle is to develop safe, efficient, and commercially viable, on-board fuel storage system for the fuel cell vehicle or natural gas vehicle that use highly compressed gaseous fuel such as hydrogen or natural gas. This study presents the whole procedure of development and certification of a type 3 composite cylinder of 207bar service pressure and 70 liter water capacity, which includes design/analysis, processing of filament winding, and validation through various testing and evaluation. Design methods of liner configuration and winding patterns are presented. Three dimensional, nonlinear finite element analysis techniques are used to predict burst pressure and failure mode. Design and analysis techniques are verified through burst and cycling tests. The full qualification test methods and results for validation and certification are presented.

• Membrane Journal
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• v.19 no.1
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• pp.1-6
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• 2009

Hydrogen energy id the 2nd clean energy able to be produced from the abundant resources, and the products of combustion or reaction do not spread an environmental pollution. Also, the hydrogen is the chemical media easily to transport and storage as energy source. The hydrogen production technology using by water splitting through electrolysis could be usable as a permanent renewable energy system without the environmental impact. The key technology of high temperature steam electrolysis is the development of an electrolyte rapidly to conduct an oxygen or proton ion decomposed from water. Subsequently, the important technology is to keep the joining technology of an electrolyte membrane and electrode materials to affect into the current efficiency.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.463-469
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• 2012

Solar thermochemical syngas and hydrogen production process bv redox system of metal oxide was performed under direct irradiation of the metal oxide on the SiC ceramic foam device using solar simulator. $CeO_2/ZrO_2$ nanotube has been synthesized by anodic oxidation method. Syngas and hydrogen production process is one of the promising chemical pathway for storage and transportation of solar heat by converting solar energy to chemical energy. The produced syngas had the $H_2/CO$ ratio of 2, which was suitable for methanol synthesis or Fischer-Tropsch synthesis process. After ten cycles of redox reaction, $CeO_2$ was analyzed using XRD pattern and SEM image in order to characterize the physical and chemical change of metal oxide at the high temperature.